<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        .container {
            width: 500px;
            height: 500px;
            position: absolute;
            left: 50%;
            top: 50%;
            transform: translate(-50%, -50%);
        }

        .box{
            width: 500px;
            height: 500px;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .box1{
            width: 200px;
            height: 200px;
            background: plum;
        }

        .content{
            width: 500px;
            height: 500px;
            display: table-cell;
            text-align: center;
            vertical-align: middle;
        }

        .box2{
            width: 200px;
            height: 200px;
            background: plum;
            display: inline-block;
        }
    </style>
</head>

<body>
    <div class="container">
    </div>

    <div class="box">
        <div class="box1"></div>
    </div>

    <div class="content">
        <div class="box2"></div>
    </div>
</body>

</html>